Water-cooled engine control

ABSTRACT

An electronic control unit for a combustion engine having a water coolant passageway in heat transfer adjacency to the unit and adapted to remove heat from the unit. An ECU for combustion engine, comprising: electrical input circuits, electrical control circuits, electrical fuel injection output drive circuits, electrical oil pump output drive circuits and electrical ignition circuits. An ECU is disclosed which is adapted to verify firing of the ignition coils of the engine.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional PatentApplication serial No. 60/109,716 filed Nov. 24, 1998.

BACKGROUND OF THE INVENTION

[0002] This invention relates generally to combustion engines and, moreparticularly, to electronic control units for such engines.

[0003] Known combustion engines for use with watercraft include anair-cooled electronic control units (ECU) for controlling at least someoperations of the engine. With increased processing demand and anincrease in the number of ECU electronic components, a need hasdeveloped for improved cooling as compared to the cooling provided bythe known air cooling configurations. In addition, with known ECUconfigurations, testing of the ignition coils has been limited totransmitting commands to cause such coils to fire without verificationas to whether the coils actually did fire.

BRIEF SUMMARY OF THE INVENTION

[0004] It would be desirable to increase the amount of circuitry in theECU to include heat-generating circuitry without the generated heatcausing the ECU to malfunction. It would also be useful to allow the ECUto check the ignition coils and determine whether or not they areoperational.

[0005] One embodiment provides a water cooled ECU in order to allow moreelectrical components to be present in the ECU. The ECU also is able tonot only cause the ignition coils to fire, but also to verify whethersuch coils did, in fact, fire.

[0006] A water-cooled configuration for the ECU provides enhancedcooling as compared to known air-cooled configurations. The water-cooledECU is configured to contain portions of the ignition circuit, which haspreviously been outside the ECU.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a top front perspective view of a marine outboardcombustion engine, incorporating a preferred embodiment of theinvention;

[0008]FIG. 2 is a top rear perspective view of the engine of FIG. 1;

[0009]FIG. 3 is a top, left, rear perspective view of an electroniccontrol unit for use with the engine of FIG. 1;

[0010]FIG. 4 is a top external view of the ECU of FIG. 3;

[0011]FIG. 5 is a front elevational external view of the ECU of FIG. 4;

[0012]FIG. 6 is a bottom view in cross-section taken along lines 6-6 ofFIG. 5;

[0013]FIG. 7 is a side external view of the forward connector of the ECUof FIGS. 3-6, taken along lines 7-7 of FIG. 4;

[0014]FIG. 8 is an external view of the rear connector of the ECU ofFIGS. 3-6 taken along lines 8-8 of FIG. 5 and lines 7-7 of FIG. 6;

[0015]FIG. 9 is a block diagram illustrating the information flowthrough the ECU of FIGS. 3-6;

[0016]FIG. 10 is a block diagram illustrating a power distribution panelfor the ECU of FIGS. 3-6;

[0017]FIG. 11 is a block diagram of the sensor and circuit switch moduleof the ECU of FIGS. 3-6;

[0018]FIG. 12 is a block diagram of the ignition circuit of the ECU ofFIGS. 3-6 for a four-cylinder engine;

[0019]FIG. 13 is a block diagram of the ignition circuit of the ECU ofFIGS. 3-6 for a six-cylinder engine;

[0020]FIG. 14 is a block diagram of a fuel injector circuit for afour-cylinder engine, showing the connections to the ECU of FIGS. 3-6;

[0021]FIG. 15 is a block diagram of a fuel injector circuit for asix-cylinder engine, showing the connections to the ECU of FIGS. 3-6;

[0022]FIG. 16 is a left, front, top exterior exploded perspective viewin partial cutaway to show the cooling water flow through a marineoutboard engine adapted for use with the ECU of FIGS. 1-3;

[0023]FIG. 17 is a flow diagram showing how the coolant flow system ofFIG. 16 is connected to the ECU of FIGS. 1-3; and

[0024]FIG. 18 is a schematic drawing of the electric wiring for themarine engine of FIGS. 1-2 showing how the main engine parts areelectrically connected.

DETAILED DESCRIPTION OF THE INVENTION

[0025]FIG. 1 is a top front perspective view of an electronic controlunit (ECU) 100 connected to a marine outboard combustion engine 101.Unit 100 is located in a powerhead 102. Powerhead 102 also contains aflywheel cover 103 and a capacitor 104. It will be understood that thislocation of ECU 100 is exemplary and ECU 100 could be located anywherethat is practical and desired on engine 101. ECU 100 includes awater-cooled (in a manner described below) housing containing amicroprocessor that receives sensor, switch and electrical signals andpower that provides information on engine operating conditions inpowerhead 102, interprets those signals, and generates commands to thevarious components that are connected to ECU 100. In addition tocontrolling engine operation, ECU 100 has a number of other importantprogrammed functions. ECU 100 stores service codes, activates a warningsystem, provides choke-less cold starting, controls engine monitoringgauge lights, generates a tachometer signal, prevents excessive engineRPM, provides an initial break-in oil ratio that is twice normal rate,controls electric fuel pump operation, and records engine operatinghours. ECU 100 is an EEPROM design, so service codes will not be lost ifbattery power to ECU 100 is lost. Stored service codes that have notreoccurred for 15 or more running hours will automatically be eliminatedfrom memory.

[0026] A crankshaft position sensor 106 is located on a first side ofpowerhead 102, and a throttle position sensor 108 and starter solenoid110 are located on a second side of powerhead 102. In addition, timingpointers 112 and 114 are on flywheel cover 103 for purposes of timing,respectively, the four cylinder and the six cylinder version of engine100.

[0027]FIG. 2 is a top, rear, perspective view of marine outboardcombustion engine 100. In FIG. 2, ECU 100 is mounted adjacent capacitor104 and above and behind flywheel cover 103, although, as stated above,this position could be anywhere that is desired. ECU 100 has twoelectrical harness connectors, a forward connector 116, and a rearconnector 118. Engine 101 also includes a main power relay 120, a watertemperature switch 122 and a water temperature sensor 126. A vaporseparator vent hose 124 leads to a vapor separator (not shown). A waterhose 128 from the vapor separator wraps around ECU 100. Several fuelhoses 130 are connected to a fuel junction block 132. Engine 100 has athrottle position sensor 108 used to determine the actual throttleposition.

[0028]FIG. 3 is a perspective view of ECU 100. A water passage 134 isdisposed in heat transfer adjacency to a portion of ECU 100. Waterpassage 134 has a water hose connector 136, 138 at either end, andserves as a heat exchanger to cool ECU 100 by transferring heat from ECU100 into water flowing through water passage 134. Water passageway 134lies horizontal, but could be oriented vertically, if desired. The flowthrough passageway 134 could be driven by a water pump or could be byconvection, since hot water naturally rises and cold water settles.Convection flow, which occurs naturally in response to heating of watermakes the coolant flow more dependable since it depends solely onphysical principles without moving parts. Pump driven flow is likely tobe at higher flow rates and thus able to cool more effectively, but ismore likely to be subject to mechanical breakdown. Which is used dependson the amount of cooling needed.

[0029] In addition to sensors (described below) located outside of ECU100, any desired number of sensors 139 are located inside ECU 100.Sensors 139 can be conventional sensors. Sensors 139 can, by way ofexample, be sensors for barometric pressure, control unit temperature,alternator voltage (26 volts), battery voltage (12 volts), and ROMverification.

[0030] The barometric pressure sensor is a silicon pressure sensorhaving diaphragm-sealed air passages that generates an alternatingcurrent voltage signal. It senses ambient air pressure through ascreened port that is open to atmosphere. The barometric pressure signalenables ECU 100 to compensate for changes in altitude and air density upto 14,000 feet (4267 m) so it can adjust fuel flow accordingly. Ifsensed values are out of limits, or the sensor or circuit fails, ECU 100will turn on a “CHECK ENGINE” light, and store a service code.

[0031] ECU 100 temperature sensor, also inside ECU 100, monitors fuelinjector driver circuit temperature to prevent that circuitry fromexceeding design limits. One or more fuel injectors could malfunctionshould this occur. If sensor values are out of limits, or the sensorcircuit fails, ECU 100 will turn on the “CHECK ENGINE” light, and storea service code. ECU 100 will also initiate a special “SLOW” warningsystem, but only if excessive temperature is the failure mode.

[0032] The 26-volt circuit sensor monitors the rectifier/regulator26-volt output. This is the circuit the powers the field injectors. Ifvoltage exceeds the expected range, ECU 100 will initiate “SLOW”, storea service code, and turn on the “CHECK ENGINE” light. Voltage below theexpected range will store a service code and turn on the “CHECK ENGINE”light, but will not put engine 101 into “SLOW”.

[0033] The RPM limiter feature of ECU 100 programming prevents enginedamage due to excessive engine speed. At 6116 RPM, fuel and ignition toeven numbered cylinders are shut off. At 6144 RPM, fuel and ignition tothe remaining cylinders are also shut off. Normal operation returnsautomatically as soon as engine speed drops down to the specified range,in this case below 6116 RPM.

[0034] The idle governor reacts to water temperature sensor values. Itchanges fuel pulse width to maintain engine speed within a range of 650RPM (warm engine) to about 850 RPM (cold engine). The governor isinactive above about 1200 rpm.

[0035] The 12-volt circuit sensor monitors rectifier/regulator 12-voltoutput. This is the circuit that supplies all 12-volt components/circuitrequirements. If voltage is out of limits, high or low, ECU 100 willstore a service code and turn on the “CHECK ENGINE” light.

[0036] The ROM verification sensor is a continual ECU self-test offactory programming. ECU 100 will turn on the “CHECK ENGINE” light andstore a service code if, at any time, a program failure is detected.

[0037] FIGS. 4-5 are top and front views of ECU 100. Water passage 134is enclosed in a metallic housing 140 that has a rounded top 144 and aflat bottom 146 adapted to fit atop a flat top surface 142 of ECU 100for good heat transfer.

[0038]FIG. 6 is a top plan view in cross-section taken along lines 6-6of FIG. 5, illustrating the circuitry within the ECU 100. The circuitryis divided into a low-power portion 148 and a high-powered portion 150.It will be understood that high-powered portion 150 is in heat transferadjacency to the water passage 134 so that the primary sources of heatgenerated by and within ECU 100 all are in heat transfer adjacency towater passage 134. Placement of water passage 134 directly on top of ECU100 and in heat transfer adjacency to high-powered portions ofelectronic circuitry enables high-powered electrical circuitry to bemore compactly and densely placed within ECU 100. As electricalcircuitry becomes more and more sophisticated, cooling of ECU 100becomes more and more important.

[0039]FIG. 7 is an external view of forward connector 116 of ECU 100 andincludes a table showing pin number, circuit description and wirecoloring code for connector 116. Coding of the 24 pins 151 labeled 1through 24 in FIG. 7 in connector 116 is merely an exemplary embodimentand not the only coding which may be used. Pins 151 could be smallerthan shown and could be electrically spaced to prevent cross signals andcross currents. Connector 116 has a plurality of pins positioned in twoparallel arrays 152, 154 of 12 pins each, commonly located within arectangular wall shield 156, but other arrangements could be utilized.For example, pins 151 and shield 156 could be located on the wiring andcorresponding sockets located in ECU 100.

[0040]FIG. 8 is an external view of rear connector 118 of ECU 100. FIG.8 includes a table showing pin number, circuit description and wirecoloring code for connector 118. It will be appreciated that coding ofthe 24 pins 157 labeled 1 through 24 in FIG. 8 in connector 118 ismerely a preferred embodiment and not the only coding which may be used.Pins 157 could be smaller than shown and could be electrically spaced toprevent cross signals and cross currents. Further, while connector 118is shown as being a plurality of pins 157 positioned in two parallelarrays 158, 160 of 12 pins each, commonly located within a rectangularwall shield 162, other arrangements could be utilized. For example, pins157 and shield 162 could be located on the wiring and correspondingsockets located in ECU 100.

[0041]FIG. 9 is a block diagram illustrating ECU 100. FIG. 9 is laid outin logic sequence showing portions that are contained within ECU 100 andthe portions that are outside of ECU 100. Specifically, sensors such aswater temperature sensor 126 and throttle position sensor 110 andvarious other sensors in powerhead 102 and elsewhere in engine 101,collectively referred to as box 164 are outside of ECU 100. The signalsfrom sensors 164 are connected through the electrical wiring harnessconnectors to input circuits 168 within the ECU 100. In addition tosensors 164 located outside ECU 100 are various sensors located insideECU 100, which are collectively numbered 166, and which were previouslyexemplified by sensors 139. Sensors 166 are also connected to inputcircuits 168. Input circuits 168 perform certain receiving, conversionand other functions with respect to those sensors and generate outputdata that is fed to control circuits 170. Circuits 170 analyze outputdata from input circuits 168 and generate control signals to variouscircuits within ECU 100. Some of these various circuits which receivecontrol signals from control circuits 170 are field injector outputdrive circuits 172, oil pump output drive circuits 174 and ignitioncircuits 178. Of particular note is that ignition circuits 178 arelocated within ECU 100, which is in contrast to prior art. This isallowed, in part, by water-cooled nature of ECU 100, such as isexemplified by presence of water passage 134 in heat transfer adjacencyto ECU 100. Circuits 178 have ability to determine whether or notignition coils have fired, since circuits 178 are within ECU 100 and arethus microprocessor based. This is in contrast to prior art ECUs whichplaced the ignition circuit outside of ECU 100 and thus did not allowsuch verification of firing. Fuel injector output drive circuits 172receive control signals from control circuits 170 and transmitoperational signals to fuel injectors 176. Oil pump output drivecircuits receive control signals from control circuits 170 and transmitoperational signals to oil pump 180. Ignition circuits 178, similarly,receive control signals form control circuits 170 and selectively allowignition power to ignition coils 182, which, in turn, provide highvoltage current at precise intervals to spark plugs 184 to generateignition sparks which power engine 101.

[0042]FIG. 10 is a block diagram illustrating a power distribution panel186 for ECU 100 and includes a table listing electrical circuitry wiringof panel 186. Panel 186 includes various relays, uses and color-codedwiring. Many of these are connections to parts of engine 101 other thanECU 100 and will thus be mentioned only by noting that they are listedin the table in FIG. 10. It will be understood that FIG. 10 is providedprimarily for purposes of background information and enablement and notas any kind of limitation. Panel 186 can include any desired number andtype of power connections or components. Panel 186 includes a 12 voltsupply 188 to ECU 100 through a fuse 192, a switched 12 volt connectionto ECU 100, a 26 volt supply 194 to ECU 100, an ECU connection 1008 tothe fuel pump relay, and any other signal which is needed to powerengine 101 under the direction of ECU 100.

[0043]FIG. 11 is a block diagram of sensor and circuit switches includedwithin external portion 196 of the sensing and switching system forengine 101 with which ECU 100. FIG. 11 shows switches and sensors thatare external to ECU 100 of FIGS. 3-6. FIG. 11 shows sensors 164 that areconnected through front electrical wiring harness connector 116 to inputcircuits 168 in ECU 100. It is preferable to use a separate wiringharness connector for the sensors/switches and the commandcontrols/power signals. Among the sensors and switches in FIG. 11 arewater temperature sensor 198, water temperature switch 200, shiftinterrupt switch 202, crankshaft position sensor 106,rectifier/regulator 204, capacitor 104, power distributions panel 186,diagnostic connector 206, 208, throttle position sensor 134, airtemperature sensor 210 and an oil pressure switch 212. The color codingof wiring used to interconnect these circuits and ECU 100 are listed ina table below FIG. 11 for correspondence with coding shown in FIG. 7 andFIG. 8. As noted previously, there is no particular magic tocolor-coding used, except that it is intended to make repair jobs easierfor repairmen. In this regard, special attention is directed todiagnostic connector 206, 208 that connects to ECU 100 and thereby tostart a diagnostic routine within ECU 100 and also connects to adiagnostic unit (not shown) such as might be used by a repairman. Alegend is included with FIG. 11 in order to identify various sensors andswitches which are shown on FIG. 11.

[0044] Air temperature sensor 210 monitors temperature of air enteringan air silencer. Sensor 210 is a positive temperature coefficientthermistor. A thermistor, as used herein, is a resistor whose resistancechanges with temperature and alters voltage values accordingly. Whentemperature increases both resistance and voltage also increase. Whentemperature decreases, resistance and voltage likewise decrease. Sensor210 receives a voltage signal from ECU 100, another wire provides aground circuit back to ECU 100. ECU 100 uses this signal to adjustair/fuel ratio in accordance with changes in incoming air temperatures.If sensor 210 senses values out of limits, or sensor 210 or its circuitfails, ECU 100 will store a service code and turn on the “CHECK ENGINE”light.

[0045] Water temperature switch 200 is located in starboard cylinderhead (shown below). Switch 200 threads into a seat (not shown) in thewater passage of the starboard cylinder head, but does not actuallycontact water. Switch 200 monitors water temperature to protect againstan engine overheating. Its operation differs somewhat from the watertemperature sensor 198 in that switch 200 is an on/off switch, not athermistor. Switch 200 receives a voltage signal from ECU 100, and ifpowerhead temperature exceeds switch limits, a circuit grounds and ECU100 will initiate SLOW, store a service code, and turn on a “WATER TEMP”light.

[0046] The water temperature sensor 198 is located in the port cylinderhead (shown below.) It threads into a seat in the water passage of thehead, but does not actually contact the water. The sensor has a dualpurpose; it provides data to ECU 100 primarily for use in adjusting theair/fuel ratio during engine warm-up, and it will trigger the “systemcheck” warning gauge when engine 101 overheats. The water temperaturesensor is also a positive temperature coefficient thermistor, a resistorwhose resistance changes with temperature. When temperature increases,both resistance and voltage also increase. Sensor 198 receives a voltagesignal from ECU 100, and another wire provides a ground circuit back toECU 100. ECU 100 uses this signal to adjust the air/fuel ratio inaccordance with changes in powerhead water temperature. If sensor 198senses values are above the limits, indicating an engine over heatcondition, ECU 100 will initiate SLOW, store a service code, and turn ona “WATER TEMP” light.

[0047] The shift interrupt switch, which is used for six-cylinderengines only, is in contact with a shift lever. The switch is normallyopen. When the button is depressed (by excessive shift loads), theswitch is closed and completes a ground circuit. ECU 100 momentarilyshuts off fuel and spark to three cylinders (for example, Nos. 2,4,6) tomomentarily reduce drive train loads and ease shifting, thenautomatically restores normal engine operation. The signal threshold canbe, for example, 2144 RPM and the shift interrupt function will not workabove it. Switch 202 must be released to its normally open positionbefore the interrupt circuit can be actuated again. ECU 100 provides avoltage signal to the shift interrupt switch; another wire connects theswitch to a powerhead ground. If the switch or its circuit fails, ECU100 will store a service code and turn on the “CHECK ENGINE” light.

[0048] The throttle position sensor 134 is a rotary potentiometerlocated near flywheel cover 103, and contacts a vertical throttle shaft.Sensor 134 receives a voltage signal from ECU 100. As the throttle leveris rotated, ECU 100 receives a return voltage signal through a secondwire. This return voltage signal is relative to the position of thethrottle shaft. As the throttle opens, voltage increases. As thethrottle closes, voltage decreases. A third wire completes the groundcircuit back to ECU 100. If sensed values are out of limits, or sensor134 or its circuit fails, ECU 100 will turn on the “CHECK ENGINE” light,store a service code, and automatically reduce engine speed to idle.Once a throttle position circuit fault has been detected by sensor 134and ECU 100, engine 101 will not accelerate above idle speed. To reset,engine 101 must be stopped and the fault corrected.

[0049] The crankshaft position sensor 106 is an electro-magnetic devicethat generates a magnetic field that is interrupted by flywheel encoderribs passing through it. This produces an alternating current voltagesignal directly related to flywheel speed. Crankshaft top dead centerposition is determined by encoder rib spacing. Sensor 106 feeds theflywheel encoder data to ECU 100, which calculates timing position andengine speed. ECU 100 generates a tachometer signal, and controls fuelinjector and ignition operation. Sensor 106 is located adjacent toflywheel cover 103 and, for example, requires a 0.050 plus or minus0.005 inches (1.27 plus or minus 0.127 mm) sensor-to-flywheel air gap tooperate properly. If sensor 106 fails, engine 101 will not run. If theair gap is incorrect, engine 100 will run erratically. A sensor 106 thatis damaged or out of adjustment will cause ECU 100 to turn on the “CHECKENGINE” light and store a service code, but only if the failure occurswhile engine 101 is running.

[0050] Diagnostic connector 206 provides for a connection to a suitablecomputer having diagnostic software thereon, such as the proprietary OMCFFI™ diagnostic software. The software allows a technician to do manyuseful things, such as actuate individual fuel injectors and spark plugson individual cylinders, test oil injector operation, run the electricfuel circulation pump, perform cylinder drop tests, display real-timesensor values and system voltages, display switch conditions and engineoperating parameters, verify engine and computer timing, retrieve andclear stored service codes, display accumulated engine hours, displayrecorded engine hours within six operational speed ranges, initiate areplacement powerhead oil break-in program, print and save the servicereport, install and service a replacement injector, and install andservice a replacement electronic control unit. This software could alsobe designed to include any other desired service function, and isgenerally described here only for purposes of completeness. The specificdiagnostic software is not part of the present invention, but isdescribed in detail in a separate co-pending application.

[0051]FIG. 12 is a block diagram of portion 214 of ignition circuit178,182,184 of powerhead 102 which is external to ECU 100 and whichconnects to internal portion 178 of overall ignition circuit 178, 182,184 for a four-cylinder engine. Portion 214 includes ignition coils 182and spark plugs 184, although coils 182 are shown in more detail in FIG.12. Portion 214 connects primarily to connector 118, but also includescrankshaft position sensor 106, which is connected to input circuit 168of ECU 100 through connector 116. The power connections to and frompower distribution panel 186 are made through connector 118 to dualignition coils 216, 218 for the cylinders as shown. Coils 216, 218 leadto spark plugs 220, 222, 224 and 226. Circuit 178, 182, 184 furtherincludes a key switch 228 to provide security to the starting functionof engine 101.

[0052]FIG. 13 is a block diagram of portion 230 of another ignitioncircuit 178,182,184 of powerhead 102 102 which is external to ECU 100and which connects to internal portion 178 for a six-cylinder engine. Itwill be understood that this ignition circuit 178,182,184 connectsprimarily to connector 118, but also includes crankshaft position sensor106, which is connected is to input circuits 168 through connector 116.The power connections to and from the panel 186 are shown to beconnected through connector 118 to the ignition coils 232, 234, 236, and238. Coils 232, 234, 236, and 238 are, in turn, connected to spark plugs240, 242, 244, 246, 248 and 250. A key switch 252 provides security tothe starting function of engine 101.

[0053]FIG. 14 is a block diagram of a fuel injector circuit 176 for afour-cylinder engine, showing connections to fuel injector output drivescircuits 172 of ECU 100. As with the ignition circuit 178,182,184, powerfor operation of fuel injectors is provided by power distribution panel186 through rear electrical wiring harness connector 118. Power is thenprovided within ECU 100 to fuel injector output drive circuits 172, andfrom circuits 172 out of ECU 100 through rear electrical wiring harnessconnector 118 to four fuel injectors 254, 256, 258 and 260 of circuit176.

[0054]FIG. 15 is a block diagram of a fuel injector circuit 262 for asix-cylinder engine, showing connections to fuel injector output drivescircuits 172. As with the ignition circuit 178,182,184, power foroperation of fuel injectors is provided by power distribution panel 186through the rear electrical wiring harness connector 118 to fuelinjector output drives circuits 172, and from circuits 172 back throughrear electrical wiring harness connector 118 to six fuel injectors 264,266, 268, 270, 272 and 274.

[0055]FIG. 16 is a left, front, top exterior exploded perspective viewof a portion of an outboard engine in partial cutaway to show oneexemplary flow pattern for a coolant system 279 for cooling water flowthrough engine 101 when adapted for use with ECU 100 of FIGS. 1-3.Cooling water enters lower unit 276 through water intake openings 278and passes upwardly through lower unit 276 into a mid-section 280 intopowerhead 102. This cooling water them circulates within powerhead 102to cool appropriate components and then exits downwardly throughmid-section 280 and out of water vents 282 or out of prop mountingcavity openings 284. This completes the water cooling circuit. The waterwill be circulated in powerhead 102 in the manner shown below in FIG.17. It will be recognized that although an outboard engine 101 is shown,and inboard or inboard/outboard engine could be substituted for engine101. It will also be understood that the water may flow through the

[0056]FIG. 17 is a flow diagram of the coolant flow system 286 of engine101 connected to ECU 100 and the fuel supply connected to the fuelinjectors in order to fuel engine 101. System 286 and the fuelsupply/fuel return system 288 for a 4-cylinder engine would be similarfor a 6-cylinder engine, except there would be additional fuel supplyand return lines. In coolant system 279 and coolant system 286, waterfrom the environment enters lower unit 276 via a port adapter 290 and toa water pump 279. From pump 279, water passes through a mid-section 280into powerhead 102 to the inlet of a unit 292 through an inlet waterline294. This coolant then flows from unit 296 through an outlet 297 andthen through a coolant supply line 298 to the inlet 136 of water passage134, through water passage 134, out of the outlet 138, and then onthrough a cooling water drain line 300 and then back to the environmentthrough the lower unit 276. This cools at least a portion of ECU 100.

[0057]FIG. 17 also shows the fuel supply system 288. Fuel enters system288 through the fuel supply hose 290 from a fuel tank 293 past a sensor294 and a second fuel line 296 to a fuel regulator 298. The fuel thenpasses through the jacket of the unit 292 to a fuel pump 300. From thefuel pump 300, the fuel passes through a third fuel line 302 to a fueldistribution block 304, where it is divided into four supplies for fourfuel injectors 254, 256, 258 and 260. Any excess fuel from the fuelinjectors is returned via fuel return lines 306, 308, 310, 312 to asecond fuel junction block 314. From this second fuel junction block 314the fuel then returns through a return line 316 to the fuel regulator298 to repeat the fuel supply cycle. Fuel return line 316 is providedwith a test point 318 for purposes of verifying adequate fuel flow.

[0058]FIG. 18 is a schematic drawing of the overall electric wiringsystem 186 for the engine 101 exemplifying how the main engine parts canbe electrically connected. Power distribution panel 186 provides powerfor system 186. The sensor circuits lead to connector 116. Ignitioncircuit 216 is connected to ECU 100 through connector 118. Crankshaftposition sensor 106 is part of system 186. Fuel injector circuits 176appear, and fuel supply tank 293 is seen.

[0059] While the invention has been described in terms of variousspecific embodiments, those skilled in the art will recognize that theinvention can be practiced with modification within the spirit scope ofthe claims.

What is claimed is:
 1. A method of cooling an ECU for an internal combustion engine, said method comprising the steps of: introducing water into the engine; passing the introduced water in heat transfer adjacency to at least a first part of the ECU to heat the water and cool the part; removing the heated water from the vicinity of the part.
 2. A method in accordance with claim 1 wherein the engine is a marine engine and the method further comprises the step of inserting a lower unit of the engine into a body of water so that water is introduced into the engine through a lower unit of the engine.
 3. A method in accordance with claim 1 further comprising the step of passing the water through the engine in close proximity to and, in heat transfer adjacency with, a fuel pump.
 4. A method in accordance with claim 1 further comprising the step of generating an ignition current within the ECU and selectively periodically supplying that current to a plurality of ignition coils outside of the ECU.
 5. A method in accordance with claim 4 further comprising the step of passing the water through a passageway in heat transfer adjacency to, but electrically isolated from, a portion of the ECU which is generating the ignition current.
 6. An ECU for a combustion engine, said ECU comprising: a heat-producing part; a water coolant passageway in heat transfer adjacency to said part and adapted to remove heat from the part.
 7. An ECU in accordance with claim 6 further comprising a heat-generating electrical circuit within the part in heat transfer adjacency to the water coolant passageway.
 8. An ECU in accordance with claim 7 wherein said electrical circuit has a high power portion and a low-power portion, the high power portion is in the first part, and the coolant passageway is in heat transfer adjacency to the high power portion.
 9. An ECU in accordance with claim 6 wherein the ECU further comprises a housing and the water passageway is integral with the housing.
 10. An ECU in accordance with claim 9 wherein the water passageway is disposed on top of the ECU.
 11. An ECU in accordance with claim 9 wherein the water passageway is disposed adjacent one edge of the top of the ECU.
 12. An ECU in accordance with claim 6 wherein the water passageway has an inlet connector and an outlet connector, both adapted to receive a water hose.
 13. An ECU for a combustion engine, said ECU comprising: a housing; electrical input circuits, located within the housing; electrical control circuits, located within the housing; electrical fuel injection output drive circuits, located within the housing; electrical oil pump output drive circuits, located within the housing; and a portion of the electrical ignition circuit immediately prior to the ignition coils located within the housing, so that the ECU can communicate electrically with the ignition coils.
 14. An ECU in accordance with claim 13 further comprising: a water coolant passageway in heat transfer adjacency to at least one of the electrical circuits and adapted to remove heat from such adjacent one of the circuits.
 15. An ECU in accordance with claim 14 wherein: said adjacent one of the electrical circuits has a high-power portion and one or more of the electrical circuits has a low-power portion, and both the high-power and low-power portions are within the ECU, and the coolant passageway is in heat transfer adjacency to the high-power portion.
 16. An ECU in accordance with claim 13 wherein the engine is a marine engine operatively controlled by the ECU.
 17. An ECU in accordance with claim 16 wherein the engine is an outboard engine.
 18. An ECU in accordance with claim 16 wherein the engine is an inboard engine.
 19. An ECU in accordance with claim 16 wherein the engine is an inboard/outboard engine.
 20. An ECU in accordance with claim 16 wherein the marine engine is water-cooled.
 21. A coolant kit for an ECU of an internal combustion engine comprising: a water passageway adapted to be placed in heat transfer adjacency to a first part of the ECU and having an inlet and an outlet; a water inlet conduit adapted to be connected to a source of liquid coolant flowing through the engine and to an inlet of the water passageway and to provide fluid communication therebetween; a water outlet passageway adapted to be connected to a liquid coolant removal device and to an outlet of the water passageway and to provide fluid communication therebetween, so as to dispose of water exiting the water passageway and to conduct heat away from the ECU.
 22. A kit in accordance with claim 21 further comprising means for connecting the water passageway to the top of the ECU.
 23. A kit in accordance with claim 21 wherein the water passageway is enclosed in a housing having a rounded portion and a flat portion, the flat portion being adapted to be placed in close contact with a corresponding flat portion of an ECU.
 24. An ECU for an internal combustion engine comprising an ignition circuit adapted to verify firing of the ignition coils.
 25. The ECU of claim 24 wherein the ignition circuit is located within the ECU and the ignition coils are located outside the ECU.
 26. The ECU of claim 24 further comprising a water passage adjacent a heat generating portion of the ECU for cooling the heat generating portion.
 27. A method of cooling a heat-generating electrical circuit in a motor used for propulsion through water, the method comprising the steps of: (a) diverting through the motor a portion of the water through which the motor is providing propulsion; and (b) routing the water in heat transfer communication with the circuitry.
 28. The method of claim 27 wherein the electrical circuit is at least part of an ECU.
 29. The method of claim 27 wherein the motor is an internal combustion engine.
 30. The method of claim 27 wherein the heat transfer communication includes heat transfer by convection of the diverted water.
 31. The method of claim 27 wherein the heat transfer communication includes movement of the diverted water by convection.
 32. The method of claim 27 wherein the heat transfer communication includes heat transfer by radiation from the circuitry to a body and conduction from the body to the diverted water.
 33. A motor used for propulsion through water, the motor comprising: (a) heat-generating circuitry used in the operation of the motor; and (b) a water passageway in heat transfer communication with the circuitry, the passageway in fluid communication with, and adapted to receive water diverted from, the water through which the engine is providing propulsion.
 34. The motor of claim 33 wherein the circuitry is at least part of an ECU.
 35. The motor of claim 33 wherein the motor is an internal combustion engine.
 36. The motor of claim 31 wherein the heat transfer communication includes heat transfer by convection of water through the passageway. 